PRODUCTION How to Lick Monitoring Problems Esso, like many other refiners, couldn't buy the samplers it w a n t e d ; engineers build their own JINGINEERS are using more continuous analytical instruments on plant process streams than ever before. But one .of the major application problems—how to get a satisfactory sample—is far from being licked completely. Commercially available systems t h a t will work on specific jobs are hard to find. Until engineers c a n b u y w h a t they really want, they're making their own. Esso engineers at Baton Rouge, for instance, couldn't buy the right kind of sample system components for: • Vaporization of light hydrocarbon samples in the propane-butane boiling range. • Removal of entrained solids from the flue gas of a cat cracker. • Removal of entrained water from liquid hydrocarbon samples. So they m a d e their own. For example, they frequently had to collect samples of light liquid hydro carbons in the propane-butane boiling range. Normally this isn't a tough problem. But they had to drop from line pressures of 100 t o 300 p. s. i. down to atmospheric pressure and send a vapor sample over to the analyzer. They put a series of two or more orifices in the sample line behind a filter of the type normally used on in strument air systems. A steam jacketed line (or steam jacketed vaporization chamber) b e h i n d the orifices keeps the sample in t h e vapor state after it flashes through the orifices. But the problem was only half licked. The sample contained a trace of highly reactive material that readily polymer ized, so engineers couldn't use a pressure regulator on the outlet line to control pressure in t h e vaporizing sec tion. However, they found that a man ually adjusted bleed through a needle valve would work in place of a regu lator. And to minimize time lag in t h e sample system, they by-pass excess sample quantities around the analyzer to the process line. Although many ingenious systems have been developed for removing en trained solids from vapor samples, Esso engineers d e c i d e d they would design a system of their own. It works very well on the company's fluid cat cracker. 86
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Engineers circulate a heavy flow of gas from t h e regenerator outlet to a point near a small analyzer h o u s e and baiek t o the process through a 2-in., allwelded sample line. A small process pressure drop and a steam ejector on the return section of the line induce this circulation. A small sample from this line goes to a miniature cyclone separator equipped with a silicon car bide filter on the outiet. It c o m e s to the analyzer clean. To remove solids from t h e cyclone, engineers t a k e a by pass stream from the bottom of t h e unit and. return this stream to t h e main sample line, downstream from a re stricting valve. E n t r a i n e d water i s rough o n many continuous analyzers, particularly those involving optical measurements. And conventional knockout pots, even in conjunction with excelsior-packed fil ters, won't always guarantee 1 0 0 % pro tection. But Esso engineers say they have solved the problem of removing entrained water from liquid hydro carbons. The sample goes to a conventional knockout p o t that is drained continu ously ( by bleeding from the b o t t o m tap to a low pressure point in the p r o c e s s ) . When it leaves the knockout pot, the sample is saturated a n d frequently con tains some entrained water. So engi neers poit t h e sample through a n upflow sand filter, periodically withdrawing water from the filter. By this t i m e the sample has no entrained water b u t it is still saturated. If the sample line is steam traced and insulated to keep its temperature 30 to 50° F . a b o v e the saturation temperature, no additional water will precipitate, and the analyzer gets a clean sample. After analysis, the sample is metered and returned through another knockout p o t to the process stream. ( T h e second knockout pot prevents back flow of a n y water that might precipitate from cooling in the return line.) " W e have to design, fabricate and assemble entire sampling systems for most of our analytical instrument appli cations, " says Esso engineer, D o n a l d C. Field. "We usually select components at least 1 0 0 % overdesigned (on the basis of normal design practices for process equipment) / ' It isn't unusual,
he indicates, for Esso engineers to modify commercially available items. The bad feature about this practice: I t retards t h e rate at which engineers in stall continuous analytical instruments. • Miniature Process Equipment? Field says h e would like to see complete packaged sampling systems for sale, with or without the analyzer, especially for the more popular stream analyzers. But why not small-scale process e q u i p ment, h e suggests. " W e could use miniature heat exchangers, knockout pots, and filters, in addition to tempera ture, pressure, and flow regulators," h e adds. This type of equipment is avail able in m a n y cases for laboratory work, but very few items meet t h e safety re quirements for plant use. Miniature sampling equipment, Fields says, needs more development work a n d additional commercialization.
Improving Nylon Tricot Calendering hot under pres sure gives more cover ing power, smoother feel D υ PONT has applied a n established finishing process to nylon tricot to ob tain a fabric having new characteristics. The process, known as Schreiner calen dering, is entirely new to the tricot in dustry a n d gives a marked improve ment in appearance and handle, says Graham M. Richardson of Du Pont's Textile Fibers Department. Nylon tricot, although i t is popular, has some drawbacks. For example, it is rather easy to see through i n light denier. It catches your fingers when you run them over the fabric. I t does not make an effective b a s e for printed patterns. And, when heavy e n o u g h to give cover, it deforms a n d sags unevenly. Schreinered tricot has many advan tages over its predecessors, according to Richardson. Here are some: • Light denier fabrics with improved cover, handle, and thinness. • Smoother feel. • Delustered appearance with good whiteness. • More effective print base. • Single fabric with double fabric coverage. • Outerwear fabric t h a t cuts better and retains garment dimensions. Schreinering can be carried out at any point during the fiinishing of the tricot. However, most practical points seem to be in the griege ( w e t out and framed for uniform w i d t h ) , follow ing dyeing and drying, o r as a final
HASTINGS ~ VACUUM^AÙQES FOR
Highest Accuracy •
STABLE PERFORMANCE
•
RAPID RESPONSE
•
EASY TO USE Model f W 23
NEW! HASTINGS MODEL G V - 2 3 - V A C U U M GAUGE
HASTINGS
VACUUM
RONS
Μ
GAUGE
Highest accuracy in 0 to TOO micron range. Direct reading without adjustments. Mirror scale with knife edge pointer for accurate reading. Internal voltage regulator takes care of fluctuations in line voltage. Gauge tubes incorporate Hastings patented principle of noble metal compensated thermopiles for greater stability, longer life, more accurate reading. Rapid response i n leak detection.
Op
ιιιτ
EASY TO READ: Operator can read vacuum directly! EXTRA SENSITIVE in 0 - 1 0 0 micron range!
Model GV 23 vacuum scale shown actual size
SIMPLE TO USE: Enables less experienced personnel to take more accurate readings! | HASTINGS MODEL GV-3 V A C U U M GAUGE Measures 0-1000 micron range with high accuracy. Stable calibration. Current set de vice allows use with any line frequency, or with unmatched gauge tubes. Low in cost but has all advantages of ruggedness, and,, accuracy. Available with or without five position switching attachment shown. For the 0.1-20 mm. r a n g e , inquire about Hastings absolute pressure indicator. LABORATORY ACCURACY UNDER INDUSTRIAL PRODUCTION CONDITIONS! FOR MORE DETAILED INFORMATION WRITE:
HAS ΤINGS - R AYDI ST INCORPORATED
HAMPTON I, VIRGINIA FEB. 2 5, 1 9 5 7 C & E N
87
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àsbètrU Λρρϊΐβά Physics
Corporation/Pasadena/California
For U l t r a v i o l e t - V i s i b l e
Spectrophotometry
The Cary Model 11 provides performance comparable to the finest ; cost comparable to the cheapest.
S c h r e i n e r c a l e n d e r i n g of n y l o n tricot gives m a n y i m p r o v e d p r o p e r t i e s w h i l e r e t a i n i n g t h o s e w h i c h h a v e m a d e this fabric p o p u l a r . I n this s e q u e n c e , t h e control f a b r i c ( t o p l e f t ) — s c o u r e d , b u t not c a l e n d e r e d — s h o w s r e l a t i v e l y o p e n stitcL·. C a l e n d e r e d ( t o p r i g h t ) , calendered in the g r i e g e ( l o w e r l e f t ) , and c a l e n d e r e d finished f a b r i c ( l o w e r r i g h t ) s h o w h o w y a r n b u n d l e s are flatt e n e d a n d o p e n n e s s of stitch is r e d u c e d , increasing fabric opacity a n d making fabric s m o o t h e r t o t h e t o u c h C o n s i d e r i n g t h e p u r c h a s e of a recording spectrophotometer? The following comments may help you get much m o r e for your money. Most spectrophotometer users regard the Cary M o d e l 14, with its 1860 Â to 2.6 mu wavelength as t h e finest recording s p e c t r o p h o t o m e t e r available. W e h a v e been surprised to discover t h a t quite a few people d o n o t r e a l i z e t h a t t h e M o d e l 14 h a s a companion i n s t r u m e n t —the Cary M o d e l 1 1 - w h i c h gives t h e same high quality of the Model 14 at a cost comparable to the lowestprice r e c o r d i n g spectrophotometer. T h e difference between the Model 11 and t h e M o d e l 14 is in wavelength range. Of course, where t h e wider wavelength range is required, the M o d e l 14 is the finest i n s t r u m e n t available. However, for applications in the ultraviolet a n d visible ranges
(2100 A to S00O A) the Cary Model 1 1 provides the same high d e g r e e of accuracy, ruggedness, and dependability a s the Model 14, as well as its convenience and flexibility, including linear wavelength recording, speed of scanning, accessories, etc. Important performance data on the Cary Model 1 1 are outlined b e l o w .
finish. C o n d i t i o n s D u P o n t h a s found best are :
Stray Light: Less than 0.0001% over most of the range. Scanning Speeds: 1.0 A p e r second (ultraviolet region) to 125 A per second ( visible region ). Resolution: 1.0 Â or better throughout most of the range. Wavelength Accuracy: Better than 5.0 Â i n the ultraviolet region and better than 10.0 A in the visible region. Reproducibility: Better than 0.5 Â in the ultraviolet and 3.0 À in the visible region. Photometric Reproducibility: i|gpr_oducibility better than .004 in irtborbance can be achieved with the Model 11.
• What Next? D u Pont has pres e n t e d this process t o t h e tricot a n d lingerie i n d u s t r i e s , in k e e p i n g with rec e n t textile t r e n d s . T h e c o m p a n y is w o r k i n g w i t h t h e i n d u s t r y t o w o r k out p r o d u c t i o n d e t a i l s a n d to further c o m mercial a c c e p t a n c e — n o t y e t a n e s t a b lished fact. Richardson concludes: "Whether S c h r e i n e r e d nylon tricot realizes its full p o t e n t i a l d e p e n d s n o w on t h e a g g r e s siveness of t h e fabric p r o d u c e r s . " R i c h a r d s o n s p o k e b e f o r e t h e American Association for Textile T e c h n o l o g y in N e w York:.
• C a l e n d e r roll p r e s s u r e s r a n g i n g from 30 to 4 0 tons p e r 4-ft. w i d t h . • T e m p e r a t u r e s between 380° and 4 0 0 ° F. • F a b r i c s p e e d s b e t w e e n 13 a n d 20 yards per minute.
20,000 HOURS OF SERVICE WITHOUT MAJOR REPAIRS
The first Cary Model 11 was produced in 1947, and since then nearly every leading analytical laboratory in the United States — and many abroad — has acquired one or more Model l l ' s . The performance, flexibility* and reliability of the Model 11 have been proved in all kinds of research and control applications. One of the first instruments to be manufactured— Serial Mo. 2 —was recently overhauled at the factory after having been i n use twelve hours per day for over six years without requiring any 88
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service other than routine maintenance. This instrument has now begun a second stint of reliable service w h i c h will undoubtedly run into additional thousands of hours. FREE BULLETIN If your spectrophotometer applications are in the visible or ultraviolet range, investigate the many advantages of the Cary Model 11. For complete infonnation write to Applied Physics Corporation, 362 West Colorado Street, Pasadena 1, California, for Bulletin CN-21.
• Hanson-Van Winkle-Munning has improved its Cadalume cadmium plating process t o g i v e b r i g h t deposits w i t h low bright e n e r c o n s u m p t i o n . New C a d a l u m e p r o c e s s uses t w o b r i g h t e n e r s — C a d a l u m e M a k e - U p B r i g h t e n e r for fresh b a t h s and C a d a l u m e B r i g h t e n e r for m a i n t e n a n c e a d d i t i o n s . Results: brightness ιαρ 1 0 % ; b r i g h t e n e r life u p 4 0 0 % ; plating speeds u p 1 0 % , accord ing to c o m p a n y tests.
